In the past there have been numerous efforts to provide vehicles which include lifting structure so that the vehicle may be repaired. Jacks or lifting devices are old in the art. A representative prior art patent is that of U.S. Pat. No. 1,168,906, which is a screw-type jack, see FIG. 3. Lifting devices have been installed on vehicles, such as the air spring lift device of U.S. Pat. No. 3,064,994. Additionally, various types of jacks or lift devices have been installed on vehicles which are turned in one fashion or another from a horizontal attitude into a vertical attitude and then extended for the purpose of lifting the vehicle, see, for example, U.S. Pat. Nos. 2,233,732; 2,237,167; 2,442,881; and 3,288,436; these may be referred to as the tilt and lift type. Also included in this type of device is U.S. Pat. No. 3,860,216 which includes an arm and elbow type relationship for the tilt and swing action. Finally, U.S. Pat. No. 2,162,931, is for a lifting jack of a pneumatic type which is mounted to the wheel zone and which extends vertically. This invention is of a hydraulically operated lifting jack which is mounted to a vehicle and which includes a straight line action of extension or retraction. It differs from that of U.S. Pat. No. 2,162,931 in that it is hydraulically operated as opposed to pneumatically and includes a two-way valve, one which causes the piston to extend and the other to cause the piston to retract. The positive two-way action is not present in U.S. Pat. No. 2,162,931 which is pneumatically driven as opposed to hydraulically driven.